Adhesives for bonding together the same kind of materials such as a resin and a resin, or different kinds of members such as a resin and a metal have been heretofore known. For these adhesives, resin compositions are generally used. For example, in a laminated film to be used as a packaging material for a cell, an adhesive composed of a resin composition is used for bonding a base material layer formed of a resin and a metal layer to each other.
For example, in a packaging material for a cell, a polyurethane-based adhesive is often used as an adhesive for bonding a base material layer and a metal layer to each other. However, it takes a long time to cure a polyurethane-based adhesive. Accordingly, in a step of bonding a base material layer and a metal layer to each other, an aging step of performing heating for a long time is provided for improvement of adhesive strength after the base material and the metal material are laminated to each other with an adhesive interposed therebetween.
However, there is the problem that when a long-time aging step is provided, the lead time increases. For solving the problem, for example, Patent Document 1 discloses an adhesive composition for lamination which includes an ionizing radiation reactive group, and a heat and/or humidity-dependent curing reactive group or crosslinking reactive group. Patent Document 2 discloses a method in which an ionizing radiation-curable adhesive composition containing a dimer acid or a dimer acid derivative is used to improve the adhesion of layers in a laminated film.